427101 A7 B7 經濟部中央標準局貝工消費合作社印装 五、發明説明（1 ) 本發明係有關於換流器（inverter)及其驅動方法，特 別有關於可使複數個當作負載使用的冷陰極管有效率且 穩定地點燈之同時可抑制可聽音之發生之壓電變壓器的 驅動電路及其驅動方法。 一般’壓電變壓器係藉由施加共振頻率的交流電壓 於一次側電極來產生共振，而引起機械的振動，進而由 此機械的振動於二次側電極取出昇屋之電壓的元件。此 乃與電磁變壓器相較，具有可謀求小型化且薄型化的特 徵’且可注目於液晶所形成之顯示裝置之背光電源等的 用途。如第9圖所示的昇壓特性’壓電變壓器係具有藉 由負載的阻抗來變化昇壓比的特性。又如第圖所示， 冷陰極管係為了開始放電，而具有必需高電壓的特性。 於此場合’由壓電變壓器觀察的阻抗變成非常大。其次， 若放電開始而管電流開始流，則冷陰極管的阻抗下降， 而冷陰極管的電壓急速地減少，但是若電流流至某程度 為止’則具有電壓的減少成為緩慢的特性。因此，壓電 變壓器係具有於以冷陰極管為負載的場合，在點燈開始 時可知到高昇壓比，而若管電流流過而點燈穩定，則昇 壓比降低之適用於驅動冷陰極管的特性的元件。 例如’日本特開平8_45679號公報所示，以往，已知 此種壓電變壓器的驅動電路係於一個壓電變壓器中施行 當作壓電變壓器之負載用之複數冷陰極管之串聯的點燈 的電路。此電路係顯示於第n圖。此電路係包括：換流 器1，將直流變換成高頻的交流；直流電源E，供給 __ 4 言紙張尺度CNS ) A4· < 210x797公釐) (請先閱讀背面之注意事項再填寫本頁) 衣. 訂·427101 A7 B7 Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the Invention (1) The present invention relates to an inverter and a driving method thereof, and more particularly to a cooling device that can be used as a load. A driving circuit of a piezoelectric transformer and a driving method thereof which can efficiently and stably place a cathode tube while suppressing the occurrence of audible sound. In general, a piezoelectric transformer is an element that generates resonance by applying an AC voltage of a resonance frequency to a primary electrode, thereby causing mechanical vibration, and further, the mechanical vibration is used to take out the voltage of the house from the secondary electrode. This is compared with electromagnetic transformers, and it has the characteristics of being able to be miniaturized and thinned, and it can be used in backlight power supplies for display devices made of liquid crystal. The boosting characteristic 'piezo transformer system shown in Fig. 9 has a characteristic in which the boosting ratio is changed by the impedance of the load. As shown in the figure, the cold-cathode tube system has a characteristic of requiring a high voltage in order to start discharging. In this case, the impedance observed by the piezoelectric transformer becomes very large. Secondly, when the discharge starts and the tube current starts to flow, the impedance of the cold cathode tube decreases, and the voltage of the cold cathode tube decreases sharply, but if the current flows to a certain level, the voltage decrease becomes slow. Therefore, the piezoelectric transformer system has a cold cathode tube as a load, and a high step-up ratio can be known at the beginning of lighting. However, if the tube current flows and the lighting is stable, the step-down ratio is suitable for driving the cold cathode. Element of tube characteristics. For example, as shown in Japanese Patent Application Laid-Open No. 8_45679, in the past, it has been known that a driving circuit of such a piezoelectric transformer is a series of lighting of a plurality of cold cathode tubes used as a load for the piezoelectric transformer in a piezoelectric transformer Circuit. This circuit is shown in Figure n. This circuit includes: converter 1, converts DC to high-frequency AC; DC power supply E, supply __ 4 words paper size CNS) A4 < 210x797 mm) (Please read the precautions on the back before filling (This page) Clothing. Order
I- I I hi 4 a τ 1 ο ι _________B7 五、發明説明（2 ) 力至換流器ι ;壓電變壓器2，輸入交流電壓至一次側 電極2a ’而利用壓電效果，進而由二次侧電極2b輸出被 昇壓之高壓的交流電壓ν〇 ;冷陰極管3，當作負載而複 數根串聯於Μ電變壓器2的二次側電極2b ;電随r ,用 以檢測管電流1〇 ;二極體D，將交流電壓予以整流；積 分器4 ’由平流電路所構成；以及v-F變頻器5，依據 由積分器4所平流的電壓來控制換流器ι的共振頻率f。 其次’說明於第11圖之習知例的動作β於換流器i 中’將由直流電源E所供給的直流電壓變換成交流電壓。 被變換之頻率f的交流電壓係若被輸入至壓電變壓器2 的一次側電極2a ’則藉由壓電效果而自二次側電極2b 輸出被昇壓之尚壓之頻率f的交流電麼。此高壓之頻 率f的交流電壓Vo係被輸入至當作壓電變壓器2之負載 之複數根串聯的冷陰極管3，而於此時，流至負載的管 電流1〇係藉由電阻R而變換成交流電壓，並於以二極體 D來整流後’成為由積分器4所平流的電壓v_f變頻 器5係依據此由積分器4所平流的電壓來控制換流器ι 的共振頻率f，而變化壓電變壓器的昇壓比，藉以供給既 定的管電流1〇至負载。藉由以上之電路構造所形成冷陰 極管驅動電路，而施行複數根串聯之冷陰極管3的串聯 點燈Λ 又如第12圓所示’其他習知例係藉由以一個壓電變 壓器來使一根當作壓電變壓器之負載用的冷陰極管點燈 而施行複數根並聯點燈的電路》此第12圖的電路係包 V-- -(\ , -- (請先閲讀背面之注意事項再填寫本頁〕 訂 經濟部中央標準局員工消費合作社印製— ( CNS ) ( 210Χ297^ΙΤ 經濟部中央標準局貝工消費合作社印製 4 271 Ο 1 Λ7 〜_______ Β7 i、發明説明（3 ) 括：壓電變壓器2 ;支持機構10，物理地支持此壓電變 壓器2 ;驅動電路7 ’將直流電壓變換成交互地產生之 一相位的半波正弦波電壓’而交互地輸出至壓電變壓器2 之一次侧電極2a的兩電極；直流電源e，供給電力至驅 動電路7，頻率拂掠振盈器（sweep oscillator)6，控制驅 動電路7之二相位之半波正弦波電壓的頻率化；冷陰極 管3 ’連接於壓電變壓器2的二次側電極2b ;負載電流 比較電路8，藉由比較流至冷陰極管3的管電流ι〇與基 準值，而控制頻率拂掠振盪器6的頻率拂掠方向；以及 調光（dimming)電路9 ’輸出用以將壓電變壓器2分時 (time division)驅動的調光信號至頻率拂掠振盡器6及驅 動電路7。 其次’說明此第12圖之習知例的動作β於驅動電路 7 ’將由直流電源Ε所供給的直流電壓變換成二相位的半 波正弦波電壓，而交互地輸入至壓電變壓器2之一次側 電極2a的兩電極’藉以藉由壓電效果而自二次側電極沘 輸出被昇壓之高壓的正弦波電壓Vo。此高壓的正弦波電 壓Vo係被輸入至當作壓電變壓器2之負載而被連接的冷 陰極管3。此時，流入至負載的管電流1〇係被輪入至負 載電流比較電路’而與負載電流比較電路8内部的基準 值比較若管電流1〇較基準值小，則輸出降低作為驅動 電路7之輸出之二相位之半波正弦波電壓之頻率的信 號’而若管電流1〇較大，則輸出使頻率汰上昇的信號。 且頻率拂掠振盪器6係依據來自負載電流比較電路8的 (請先聞讀背面之注意事項再填寫本頁) 袈· 訂 本紙張尺度適用中國國家標準（CNS )八4規格（210X297公釐） 經濟部中央標準局員工消費合作社印製 鱼Ο 1 · Α7 _______Β7 五、發明説明（4 ) — ~~~^ 信號而輸出頻率汰的驅動信號至驅動電路7。因此，驅 動電路7係藉由二相位之頻率化的半波正弦波電塵而驅 動Μ電變壓器2。如此’控制壓電變壓器2的驅動頻率 flc ’而變化壓電變壓器的昇壓比，進而可供給酰定的管 電流1〇至負載^ 其次，說明調光部分。調光電路9係以較壓電變壓 器2的驅動頻率fk充份低且對眼睛不閃爍的頻率&來振 動，而輸出與被輸入之調光電壓成比例而作用比（duty ratio)之變化之二進立的調光信號至頻率拂掠振盪器6及 驅動電路7 ^若此調光信號成為高位準’則驅動電路7 係停止壓電變壓器2的驅動，而停止流至負載的管電流 1〇。頻率播掠振盈器6係藉由負載電流比較電路$的動 作而於管電流1〇停止間，保持管電流1〇停止前的驅動頻 率fk，俾使驅動頻率fk不變化至較低的方向。其次，調 光信號成為低位準，而驅動電路7再開始壓電變壓器2 的驅動，進而於管電流1〇開始流時，可使管電流1〇不變 化。 第13圖係顯示依據此第12圖之習知技術所形成的 動作波形。作為調光電路9之輸出的調光信號係在頻率 fc的周期成為高位準、低位準。由於高低準的期間係停 止作為壓電變壓器2之驅動電壓之二相位之頻率作之半 波正弦波電壓的輸出，故不自壓電變壓器2輸出高壓之 頻率fk的正弦波電壓Vo，而亦停止流至負載的的管電 流1〇。為了使冷陰極管3的亮度成為最大，經常使調光 7 (請先閱讀背面之注意事項再填寫本頁) 、?τ 本，紙張尺度適用中國國家標準（CNS ) A4規格（2丨OX297公釐） 經濟部中央標率局貝工消費合作社印製 427101 Λ7 ____B7 五、發明説明（5 ) '~~~' 化號成為低位準’而為了降低亮度，施行使高位準之期 間增長的動作。如此，藉由改變作為調光電路9之輸出 之調光信號的作用比，而使用改變流至冷陰極管3之管 電流1〇之時間間隔而施行調光的脈寬調變pWM(puise Width Modulaion)方式。 於第12圖的習知技術中，使用複數由上述電路構造 所形成壓電變壓換流器，而施行當作負載用之複數之冷 陰極管3的並聯點燈。 然而’日本特開平8-45679號公報及第12圖所示的 技術具有下列的問題點。 第一問題點係於複數根當作壓電變壓器2之負載的 冷陰極管3串聯點燈的場合，限制可串聯之冷陰極管的 數目。由對於第14圖（a)所示之壓電變壓器2之輸出電力 Pout之機械的振動速度vm的特性圖可知，壓電變壓器2 可輸出的電力Pout係大體與機械的振動速度成比 例。為了複數根串聯之冷陰極管3的點燈，一根冷陰極 管3點燈所必需要的電力成為必需要其數根份。為了自 壓電變壓器2輸出更大的電力，而必需要使機械的振動 速度vm變大，但是若此輸出電力變大，則如第14圖（b) 所示，來自周圍溫度的溫度上昇△ τ增加，同時第14圖 (c所示的效率β減少。且若機械的振動速度vm成逼vmi 為止，則造成溫度上昇△ T1急速地開始增加，而效率々 急速地減少的傾向。顧於此溫度上昇△ τ急速增加的點 △ T1及效率β急速地減少的點？7 1以後，不能夠當作高 8 本k張μ適用中國家標CNS) Α4規格（21()><297公------ (請先閲讀背面之注意事項再填寫本頁) 丨农. -56 經濟部中央標準局貝工消費合作社印裝I- II hi 4 a τ 1 ο _________B7 V. Description of the invention (2) Force to the converter ι; Piezo transformer 2, input AC voltage to the primary electrode 2a 'and use the piezoelectric effect, and then the secondary side The electrode 2b outputs the boosted high-voltage AC voltage ν〇; the cold cathode tube 3 is used as a load and a plurality of secondary-side electrodes 2b connected in series to the M electric transformer 2; the electric follower r is used to detect the tube current 10; The diode D rectifies the AC voltage; the integrator 4 ′ is composed of a smoothing circuit; and the vF inverter 5 controls the resonance frequency f of the converter ι according to the voltage advected by the integrator 4. Next, "the operation β of the conventional example illustrated in Fig. 11 in the converter i" is used to convert a DC voltage supplied from a DC power source E into an AC voltage. When the converted AC voltage of the frequency f is input to the primary electrode 2a 'of the piezoelectric transformer 2, is the piezoelectric effect to output the AC voltage of the boosted and still-pressed frequency f from the secondary electrode 2b. This high-voltage AC voltage Vo of frequency f is input to a plurality of cold-cathode tubes 3 connected in series as a load of the piezoelectric transformer 2, and at this time, the tube current 10 flowing to the load is caused by the resistance R Transformed into AC voltage and rectified by diode D to become the voltage advected by the integrator 4 v_f The inverter 5 controls the resonance frequency f of the inverter ι according to this voltage advected by the integrator 4 , And change the step-up ratio of the piezoelectric transformer, thereby supplying a predetermined tube current of 10 to the load. The cold-cathode tube driving circuit is formed by the above circuit structure, and the series lighting of a plurality of cold-cathode tubes 3 connected in series is shown in the twelfth circle. 'Other conventional examples are achieved by using a piezoelectric transformer. A circuit that uses multiple cold-cathode tubes as a load for a piezoelectric transformer to light and implement parallel lighting. The circuit in Figure 12 includes package V---(\,-(Please read the Please fill in this page again before ordering] Order printed by the Consumer Standards Cooperative of the Central Bureau of Standards of the Ministry of Economics-(CNS) (210 × 297 ^ ΙΤ 3) Including: piezoelectric transformer 2; support mechanism 10, which physically supports this piezoelectric transformer 2; driving circuit 7 'converts a DC voltage to a half-wave sine wave voltage of one phase that is generated alternately' and outputs it to the voltage alternately The two electrodes of the primary electrode 2a of the electric transformer 2; the DC power source e supplies power to the driving circuit 7, a frequency sweep oscillator 6, and controls the frequency of the two-phase half-wave sine wave voltage of the driving circuit 7. Cold The pole tube 3 ′ is connected to the secondary electrode 2 b of the piezoelectric transformer 2; the load current comparison circuit 8 controls the frequency of the frequency sweep oscillator 6 by comparing the tube current ι0 flowing to the cold cathode tube 3 with a reference value. Frequency sweeping direction; and a dimming circuit 9 'to output a dimming signal for driving the piezoelectric transformer 2 time division to the frequency sweeping exciter 6 and the driving circuit 7. Next,' this is explained The operation β of the conventional example in FIG. 12 is that the driving circuit 7 ′ converts the DC voltage supplied by the DC power source E into a two-phase half-wave sine wave voltage, and alternately inputs the voltage to the primary-side electrode 2 a of the piezoelectric transformer 2. The two electrodes' use the piezoelectric effect to output a boosted high-voltage sine wave voltage Vo from the secondary electrode 。. This high-voltage sine wave voltage Vo is inputted as a load for the piezoelectric transformer 2 and is connected Cold cathode tube 3. At this time, the tube current 10 flowing into the load is rounded to the load current comparison circuit 'and compared with the reference value inside the load current comparison circuit 8. If the tube current 10 is smaller than the reference value, then Reduced output as a drive The output of the circuit 7 is a signal of the frequency of the two-phase half-wave sine wave voltage, and if the tube current 10 is large, a signal that raises the frequency is output. And the frequency sweep oscillator 6 is based on a load current comparison circuit. 8 (please read the precautions on the back before filling this page) 袈 · The size of the paper used for this edition is applicable to China National Standards (CNS) 8-4 specifications (210X297 mm) Printed by the staff consumer cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 0 1 · Α7 _______ Β7 V. Description of the invention (4) — ~~~ ^ signal and output the driving signal of frequency to drive circuit 7. Therefore, the driving circuit 7 drives the M electric transformer 2 by a two-phase frequency-frequency half-wave sine wave electric dust. In this way, 'the driving frequency flc of the piezoelectric transformer 2 is controlled and the step-up ratio of the piezoelectric transformer is changed, so that a predetermined tube current 10 can be supplied to the load ^ Next, the dimming section will be described. The dimming circuit 9 vibrates at a frequency & which is sufficiently lower than the driving frequency fk of the piezoelectric transformer 2 and does not flicker to the eyes, and the output is proportional to the input dimming voltage and changes the duty ratio The second dimming signal to the frequency sweeping oscillator 6 and the driving circuit 7 ^ If this dimming signal becomes a high level, the driving circuit 7 stops the driving of the piezoelectric transformer 2 and stops the tube current flowing to the load 1〇. The frequency-swept vibrator 6 uses the operation of the load current comparison circuit $ to maintain the driving frequency fk before the tube current 10 stops, so that the driving frequency fk does not change to a lower direction. . Next, the dimming signal becomes a low level, and the driving circuit 7 starts driving the piezoelectric transformer 2 again, and when the tube current 10 starts to flow, the tube current 10 can be made constant. FIG. 13 shows operation waveforms formed according to the conventional technique of FIG. 12. The dimming signal output by the dimming circuit 9 becomes a high level and a low level at a period of the frequency fc. Since the period of high and low precision is to stop outputting the half-wave sine wave voltage which is the frequency of the two phases of the driving voltage of the piezoelectric transformer 2, the high voltage sine wave voltage Vo of frequency fk is not output from the piezoelectric transformer 2, Stop the tube current 10 flowing to the load. In order to maximize the brightness of the cold cathode tube 3, often dimming 7 (please read the precautions on the back before filling this page),? Τ, the paper size applies the Chinese National Standard (CNS) A4 specification (2 丨 OX297 company) (%) Printed by the Shell Standard Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 427101 Λ7 ____B7 V. Description of the invention (5) '~~~' The nickname has become a low level '. In order to reduce the brightness, increase the period during which the high level is used. In this way, the pulse width modulation pWM (puise Width) of the dimming is performed by changing the duty ratio of the dimming signal as the output of the dimming circuit 9 by changing the time interval of the tube current 10 flowing to the cold cathode tube 3 Modulaion) way. In the conventional technique shown in FIG. 12, a plurality of piezoelectric transformers formed by the above-mentioned circuit structure are used, and a plurality of cold cathode tubes 3 in parallel are used as a load for lighting. However, the technique shown in JP-A-8-45679 and Fig. 12 has the following problems. The first problem is that when a plurality of cold-cathode tubes 3 serving as loads for the piezoelectric transformer 2 are lit in series, the number of cold-cathode tubes that can be connected in series is limited. From the characteristic diagram of the vibration speed vm of the output power Pout of the piezoelectric transformer 2 shown in FIG. 14 (a), it can be seen that the output power Pout of the piezoelectric transformer 2 is roughly proportional to the vibration speed of the machine. In order to light a plurality of cold-cathode tubes 3 connected in series, the power required for lighting one cold-cathode tube 3 becomes necessary. In order to output more power from the piezoelectric transformer 2, it is necessary to increase the vibration speed vm of the machine. However, if the output power is increased, as shown in FIG. 14 (b), the temperature rises from the ambient temperature Δ τ increases, and at the same time, the efficiency β shown in FIG. 14 (c) decreases. If the vibration speed vm of the machine reaches vmi, the temperature rise △ T1 starts to increase rapidly, and the efficiency 々 decreases rapidly. This temperature rise △ τ the point of rapid increase △ T1 and the point of rapid decrease of efficiency β? 7 1 and later, it cannot be regarded as high 8 copies k sheets μ applicable to the national standard CNS) Α4 specifications (21 () > < 297 males --- (Please read the notes on the back before filling out this page) 丨 Agriculture. -56 Printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs
4271 Ο T Λ7 _____ Β7 五、發明説明（6) 效率的壓電變壓器使用。因此，成為此溫度上昇ΛΤ1及 效率β 1附近的輸出電力可說是於高效率之壓電變壓換 流器之壓電變壓器2之輸出電力pout界限值。例如，對 壓電變壓器2的壓電元件形狀為長42mm，寬10mm，厚 1mm者，以管電流i〇 = 4.4mArms來驅動成為負載之長 360mm，管徑3炉的冷陰極管3的場合，壓電變壓器2 的輸出電力界限值Pout為7W。由於驅動一根上述冷陰 極官3之場合之壓電變壓器2的輸出電力pout為3.5W， 故可將上述冷陰極管3串聯於上述壓電變壓器2的根數 係二根為界限。如上述，隨著液晶面板的大畫面化，於 管長度長的冷陰極管3用於複數燈式背光的場合，冷陰 極管的串聯自由度減少，而事實上無選擇的餘地β 第二問題點係於將複數根冷陰極管3串聯點燈而當 作壓電變壓器2之負載的場合，高度成為不均一。其理 由係若於冷陰極管3的周邊具有導電性的反射板等，則 於冷陰極管3與此反射板之間形成雜散（stray)電容。由於 電流流至此形成之雜散電容，故於冷陰極管3的高壓電 極側，管電流值變大，而亮度高，但是於低壓電極侧， 管電流值減少，進而亮度降低，此現象乃冷陰極管3的 管長愈長而被形成的雜散電容愈大，進而於串聯複數根 冷陰極管3的場合，具有更加顯著的傾向。 第三問題點係於將複數根冷陰極管3並聯點燈而當 作壓電變壓器2之負載的場合，由於各驅動頻率作、各 調光頻率fc非同步，故發生因冷陰極管3相互間之干涉 本紙張尺度適用中國國家標準（CNS ) A4^i~(21〇X297^-)— (請先閱讀背面之注意事項再填寫本頁〕 -*^τ 427101 經濟部中央標準局貝工消費合作社印製 Λ7 B7 五、發明説明（7 ) 所造成的偏差。由於頻率拂掠振盪器6存在於各壓電變 壓換流器’故即使於第9固之壓電變壓器2的昇壓特性 及第10圖之冷陰極管3的電壓-電流特性具有偏差，藉 由變化驅動頻率fk，亦可使流至各冷陰極管3的管電流 1〇均成為一定的既定值。因此，由於驅動頻率伐於各麼 電變壓換流器中成不同頻率’故藉由發生於冷陰極管3 相互間的雜散電容，而使冷陰極管機械的振動冷陰極管3 相互間耦合’進而如第15圖所示，管電流1〇被振幅調變。 在此狀態下’施以依據PWM方式的調光，而使亮度降低， 則於成為某亮度以下時會造成產生偏差的問題。又若各 調光頻率fc為非同步’則壓電變壓器2的驅動開始及停 止時的兩壓係藉由冷陰極管3相互間之雜散電容所造成 的耦合來變化流過其他冷陰極管3的管電流值，而使以 管電流1〇成為一定之方式控制驅動頻率汉的負載電流比 較電路8蒒頻率拂掠振盪器6之電路的動作受影響，進 而造成當作換流器的動作成為不穩定的問題。 第四問題點係於複數根當作壓電變壓器2之負載之 管長度長的冷陰極管3串聯點燈的場合，可聽音的產生 增大。若壓電變壓器2施行依據PWM方式的調光，則由 於壓電變壓器2的驅動電壓係成為如第13圖所示之驅動 電壓Vd的叢訊（burst)波形，故於驅動開始及停止時，驅 動頻率fk含有調光頻率fc的高頻。若藉由包含此高頻之 驅動頻率fk的驅動電壓vd而驅動壓電變壓器2，則於驅 動開始及停止時，壓電變壓器2的振動狀態成為瞬間雜 10 本紙張尺度適用中國國家標M規格（210><297公楚）-~—-- 装 訂 ~ (請先閱I背面之士意事項再填寫本頁) 427101 經濟部中央標準局員工消費合作社印製 Λ7 B7 五、發明説明（8 ) 亂的狀態，而發生振動傳導至壓電變壓器2之支持機構 10的現象。此乃成為壓電變壓器2及支持機構1〇的振 動，而成為發生可聽音的原因。於驅動管長度短之冷陰 極管3的場合，即使降低可聽音的發生’於驅動複數根 串聯之营長度長之冷陰極管3的場合，被點燈之冷陰極 官3的放電開始電壓及管電壓變高，而由於壓電變壓器2 的機械的振動速度vm增大，故易產生可聽音β 本發明之目的係提供壓電變壓器的驅動電路，其藉 由使複數換流器的驅動頻率及調光頻率同步，而使複數 冷陰極管有效率且穩定地點燈。又本發明之目的係提供 壓電變壓器的驅動電路，其於使複數冷陰極管點燈的換 流器中可防止於PWM方式的調光時成為問題之可聽音 的產生。 本發明之換流器的具體裝置包括：一第一換流器， 具有將上述將直流電壓變換成交流電壓的第一驅動裝 置、輸出利用壓電效果而將自一次側所輸入的交流電壓 從二次側昇壓之交流電壓的第一壓電變壓器、將上述第 一麼電變壓器的驅動頻率輸出至上述第一驅動電路的頻 率拂掠振盪器及比較流至連接至上述第一壓電變壓器之 第一負載之電流大小的第一負載電流比較電路，且藉由 上述第一負載電流比較電路的控制信號來控制上述頻率 拂掠振盪器的驅動頻率，而將第一負载的交流電流值控 制成一定值；以及至少一第二換流器’具有將上述被供 給上述頻率拂掠振盪器之輸出之驅動頻率的第二驅動裝 各紙张尺度通用中國國家標準（CNS ) Α4現格（210X297公釐） (請先閱讀背面之注Ϊ項再填寫本頁) "° Φ. 42710 經濟部中央標準局員工消費合作社印裂 Λ7 B7 五、發明説明（ς» ) 置、連接至第二驅動電路的第二壓電變壓器、比較流至 連接至上述第二壓電變壓器之第二負載之電流大小的第 二負載電流比較電路及可變上述第二驅動電路之輸出之 第二壓電變壓器之驅動電壓的驅動電壓控制電路，且藉 由上述第一負載電流比較電路的控制信號來控制上述驅 動電壓控制電路，而將第二負載的交流電流值控制成一 定值。 又其特徵具有以PWM方式調變第一及第二壓電變 壓器用的信號輸出至頻率拂掠振盪器及波封產生電路的 調光電路及自調光電路的信號將控制包含於驅動頻率之 頻率成分之時間分割驅動所造成之高頻的信號輸出至第 一驅動電路及驅動電壓控制電路的波封產生電路。且具 有同步驅動複數壓電變壓器之驅動頻率的裝置（第i圖的 6)、以同相位的PWM方式來調變複數壓電變壓器之驅動 電壓的裝置（第1圖的9)、藉由控制壓電變壓器之驅動電 壓的峰值而將管電流控制成一定的裝置（第1圖的1丨）及 將壓電變壓器之驅動電壓之包絡線調變成梯形波的裝置 (第1圖的12)。 本發明之壓電變壓器的驅動電路係同步驅動全部壓 電變壓器的驅動頻率。因此’由於可去除冷陰極管相互 間之浮動（floating)電容之耦合所造成之管電流的調幅， 故具有不產生冷陰極管之偏差的作用。又由於在PWM調 光方式中調光頻均被同步驅動，故壓電變壓器的驅動開 始及停止時的高壓係藉由冷陰極管相互間的浮動電容所 12 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） (請先閲讀背面之注意事項再填寫本頁)4271 Ο T Λ7 _____ Β7 V. Description of the invention (6) Use of efficient piezoelectric transformers. Therefore, it can be said that the output power near the temperature rise ΔT1 and the efficiency β1 is the output power pout limit value of the piezoelectric transformer 2 of the high-efficiency piezoelectric transformer converter. For example, when the shape of the piezoelectric element of the piezoelectric transformer 2 is 42 mm in length, 10 mm in width, and 1 mm in thickness, the tube current i0 = 4.4 mArms is used to drive the cold cathode tube 3 with a length of 360 mm and a tube diameter of 3 furnaces. The output power limit value Pout of the piezoelectric transformer 2 is 7W. Since the output power pout of the piezoelectric transformer 2 for driving one of the cold cathode electrodes 3 is 3.5 W, the number of the cold cathode tubes 3 connected in series to the piezoelectric transformer 2 may be two. As described above, with the enlargement of the liquid crystal panel, when the cold-cathode tube 3 with a long tube length is used for a plurality of lamp-type backlights, the degree of freedom of the cold-cathode tube series is reduced, and in fact there is no choice. Β Second problem The point is that when a plurality of cold cathode tubes 3 are lit in series and used as a load for the piezoelectric transformer 2, the height becomes uneven. The reason is that if there is a conductive reflective plate or the like around the cold cathode tube 3, a stray capacitance is formed between the cold cathode tube 3 and the reflective plate. Due to the stray capacitance formed by the current flowing on the high-voltage electrode side of the cold cathode tube 3, the tube current value becomes larger and the brightness is higher, but on the low-voltage electrode side, the tube current value decreases and the brightness decreases. This phenomenon is cold The longer the tube length of the cathode tube 3 is, the larger the stray capacitance is formed. Further, when a plurality of cold cathode tubes 3 are connected in series, it has a more significant tendency. The third problem is that when a plurality of cold-cathode tubes 3 are lit in parallel and used as a load for the piezoelectric transformer 2, since the driving frequencies and the dimming frequencies fc are asynchronous, the cold-cathode tubes 3 are mutually Interference between this paper applies Chinese National Standard (CNS) A4 ^ i ~ (21〇X297 ^-) — (Please read the notes on the back before filling this page]-* ^ τ 427101 Printed by the consumer cooperative Λ7 B7 V. Deviation caused by the description of the invention (7). Since the frequency swept oscillator 6 is present in each piezoelectric transformer converter, it is even boosted by the ninth piezoelectric transformer 2 The characteristics and the voltage-current characteristics of the cold-cathode tube 3 shown in FIG. 10 have deviations. By changing the driving frequency fk, the tube current 10 flowing to each of the cold-cathode tubes 3 can also be made a predetermined value. Therefore, since The driving frequency is cut into different frequencies in each transformer transformer. Therefore, the stray capacitance of the cold cathode tube 3 is generated between the cold cathode tube machinery and the cold cathode tube 3 are coupled to each other. As shown in Fig. 15, the tube current 10 is amplitude-modulated. In this state, if the dimming according to the PWM method is applied to reduce the brightness, the problem of deviation will occur when the brightness is less than a certain brightness. If the dimming frequencies fc are asynchronous, the piezoelectric transformer 2 will be driven. The two voltages at the start and stop are controlled by the stray capacitance between the cold cathode tubes 3 to change the tube current value flowing through the other cold cathode tubes 3, so that the tube current 10 is controlled in a certain way. The operation of the load current comparison circuit 8 that drives the frequency Han and the circuit of the frequency sweep oscillator 6 is affected, and the operation as a converter becomes unstable. The fourth problem lies in the fact that plural roots are used as piezoelectrics. When the cold cathode tube 3 with the long tube length of the load of the transformer 2 is lit in series, the audible sound is increased. If the piezoelectric transformer 2 performs dimming according to the PWM method, the driving voltage of the piezoelectric transformer 2 is It has a burst waveform of the driving voltage Vd as shown in FIG. 13, so when the driving starts and stops, the driving frequency fk includes the high frequency of the dimming frequency fc. If the driving frequency fk including this high frequency is used Drive The piezoelectric transformer 2 is driven by the voltage vd, and the vibration state of the piezoelectric transformer 2 becomes instantaneous when the driving starts and stops. The paper size applies the Chinese national standard M standard (210 > < 297 Gongchu)-~- -Binding ~ (Please read the details on the back of I before filling out this page) 427101 Printed by the Staff Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Λ7 B7 5. Description of the invention (8) Vibration is transmitted to the piezoelectric Phenomenon of the supporting mechanism 10 of the transformer 2. This is the vibration of the piezoelectric transformer 2 and the supporting mechanism 10, and it is the cause of the audible sound. In the case of the cold cathode tube 3 with a short driving tube length, even if the audible is reduced The sound occurs when the plurality of cold-cathode tubes 3 with a long length in series are driven, the discharge start voltage and tube voltage of the cold-cathode tube 3 being lit become high, and the mechanical vibration speed of the piezoelectric transformer 2 is high. The vm is increased, so that audible sounds are easily generated. The object of the present invention is to provide a driving circuit for a piezoelectric transformer, which synchronizes the driving frequency and the dimming frequency of a complex inverter, thereby making the complex cold cathode tube efficient and stable Location lights. Another object of the present invention is to provide a driving circuit for a piezoelectric transformer, which can prevent the generation of audible sounds that are a problem during PWM dimming in a converter in which a plurality of cold-cathode tubes are lit. The specific device of the inverter of the present invention includes a first inverter having the first driving device for converting the DC voltage into the AC voltage, and outputting the AC voltage input from the primary side from the primary side using a piezoelectric effect. A first piezoelectric transformer with a boosted AC voltage on the secondary side, a frequency sweep oscillator outputting the driving frequency of the first electromechanical transformer to the first driving circuit, and a comparison flow to the first piezoelectric transformer A first load current comparison circuit of the first load current, and the control signal of the first load current comparison circuit is used to control the driving frequency of the frequency sweep oscillator to control the AC current value of the first load To a certain value; and at least one second inverter 'having a second driving device that supplies the above-mentioned driving frequency to the output of the frequency-swept oscillator, and each paper size is in accordance with China National Standard (CNS) A4 (210X297) (Please read the note on the back before filling out this page) " ° Φ. 42710 Employee Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs 裂 7 B7 5 DESCRIPTION OF THE INVENTION The second piezoelectric transformer connected to the second driving circuit, the second load current comparing circuit comparing the magnitude of the current flowing to the second load connected to the second piezoelectric transformer, and the variable The driving voltage control circuit for the driving voltage of the second piezoelectric transformer output by the second driving circuit, and the driving voltage control circuit is controlled by the control signal of the first load current comparison circuit, and the AC current of the second load is controlled. The value is controlled to a certain value. It is also characterized in that the signals used to modulate the first and second piezoelectric transformers in PWM mode are output to a frequency dimming circuit and a dimming circuit and a self-dimming circuit of the wave envelope generating circuit. The signals are controlled to be included in the driving frequency. The high-frequency signal caused by the time division driving of the frequency component is output to the envelope generating circuit of the first driving circuit and the driving voltage control circuit. And a device for synchronously driving the driving frequency of the plurality of piezoelectric transformers (6 in FIG. I), a device for modulating the driving voltage of the plurality of piezoelectric transformers in the same phase PWM method (9 in FIG. 1), and A device for controlling the tube current to a certain value by the peak value of the driving voltage of the piezoelectric transformer (1 丨 in FIG. 1) and a device for adjusting the envelope of the driving voltage of the piezoelectric transformer into a trapezoidal wave (12 in FIG. 1). The driving circuit of the piezoelectric transformer of the present invention drives the driving frequencies of all the piezoelectric transformers synchronously. Therefore, since the amplitude modulation of the tube current caused by the coupling of the floating capacitors between the cold cathode tubes can be removed, it has the effect of not causing the deviation of the cold cathode tubes. Because the dimming frequency is driven synchronously in the PWM dimming method, the high voltage at the start and stop of the driving of the piezoelectric transformer is through the floating capacitor between the cold cathode tubes. This paper size applies the Chinese national standard (CNS ) A4 size (210X297mm) (Please read the notes on the back before filling this page)
經濟部中央楯準局員工消費合作社印裝 4 271〇 Ί Λ7 ___—______Β7 五、發明説明（1〇 ) 造成的搞合而不變化流過其他冷陰極管的管電流值，進 而"Τ防止換流器動作成為不穩定，故可避免產生偏差。 又於副方塊中，控制壓電變壓器之驅動電壓的峰值，而 將管電流控制成一定》因此，可以同一亮度來將全部冷 陰極管點燈，同時可同步驅動全部驅動頻率。此外，將 調光時之壓電變壓器之驅動電壓的包絡線調變成梯形 波-因此，可減低於管長度長之冷陰極管複數並聯點燈 時成為問題之可聽音的增大。 【發明的實施例】 其次，就圖式來詳細說明本發明的實施例。第丨圖 係本例的方塊圖。此第1圖的電路係大致由主方塊、副 方塊及調光方塊所構成。 首先，如第3圖所示，主方塊24係包括：第一壓電 變壓器2，將輸入至一次側電極2a的交流電壓由二次侧 電極2b輸出當作昇壓的交流電壓；第一冷陰極管3 ,連 接至第壓電變壓器2的二次側電極2b;第一驅動電路7， 將直流電壓變換成交互產生之二相位的半波正弦波電 壓，而交互輸出至第一壓電變壓器2的一次側電極以的 兩電極；頻率拂掠振盪器6 ’控制第一驅動電路7的驅 動頻率fk ;以及第一負載電流比較電路8，自流至第一 冷陰極管3的管電流1〇，而輸出控制頻率拂掠振盈器6 之頻率拂掠方向的信號。流至被輸入至第一負載電流比 較電路8的之第一冷陰極管3的管電流1〇係於藉由：一 電流-電壓變換電路17而變換成交流電壓後，藉由第一 (請先閲讀背面之注意事項再填寫本頁)Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 4 271〇Ί Λ7 ___—______ B7 V. Description of the invention (1) does not change the value of the tube current flowing through the other cold cathode tubes, and " Τ prevents Inverter operation becomes unstable, so deviations can be avoided. In the sub-block, the peak voltage of the driving voltage of the piezoelectric transformer is controlled, and the tube current is controlled to be constant. Therefore, all the cold cathode tubes can be turned on with the same brightness, and all the driving frequencies can be driven simultaneously. In addition, the envelope of the driving voltage of the piezoelectric transformer at the time of dimming is adjusted to a trapezoidal wave-therefore, the increase in audible sound that becomes a problem when a plurality of cold-cathode tubes with a long tube length are connected in parallel can be reduced. [Inventive Embodiment] Next, an embodiment of the present invention will be described in detail with reference to the drawings. Figure 丨 is the block diagram of this example. The circuit of FIG. 1 is roughly composed of a main block, a sub block, and a dimming block. First, as shown in FIG. 3, the main block 24 includes: a first piezoelectric transformer 2 that outputs an AC voltage input to the primary-side electrode 2a as a boosted AC voltage from the secondary-side electrode 2b; The cathode tube 3 is connected to the secondary electrode 2b of the second piezoelectric transformer 2; the first driving circuit 7 converts the DC voltage into a two-phase half-wave sine wave voltage generated alternately and outputs it to the first piezoelectric transformer alternately The two electrodes of the primary side electrode of 2; the frequency sweep oscillator 6 'controls the driving frequency fk of the first driving circuit 7; and the first load current comparison circuit 8 flows from the tube current 1 to the first cold cathode tube 3. , And output a signal that controls the frequency sweeping direction of the frequency sweeping vibrator 6. The tube current 10 flowing to the first cold-cathode tube 3 input to the first load current comparison circuit 8 is converted into an AC voltage by a current-voltage conversion circuit 17, and then the first (please (Read the notes on the back before filling out this page)
427101 經濟部中央標準局員工消費合作社印繁 Λ7 B7 五、發明説明（11 ) 整流電路18而被變換成直流壓。且在第一比較器19將 管電流Ιο的既定值與基準電壓Vref比較。第一比較器19 的輸出信號係於由管電流1〇所得之直流電壓較基準電壓 Vref大的場合，輸出使第一壓電變壓器2之驅動頻率汰 上昇的信號至頻率拂掠振盪器6。另一方面，於直流電壓 較基準電壓Vref小的場合，輸出使第一壓電變壓器2之 驅動頻率fk下降的信號。被輸入此信號的頻率拂掠振盪 器6係在積分電路21將第一比較器19之二進位的輸出信 號變換成類比量的信號，而輸出至VC022及比較器20。 產生對應於此類比量之輸出信號之頻率的VC022係 輸出驅動頻率fk之二倍之頻率的振盈電路，雖然此振盪 頻率係積分電路21愈高則愈低，但是於比較器2〇比較 積分電路21的輸出電壓與基準電壓Vmax，而於輸出電 壓超過基準電壓Vmax時，亦即於振盪頻率下降至由基準 電壓Vmax所決定的最低頻率為止的場合，輸出重置 (reset)信號至積分電路21 ’而將VCC22的振盪頻率自最 低頻率高速地拂掠至最高頻率為止^ VCC22係輸出自此 最低頻至最高頻率為止之頻率範圍内之三角波fvc〇及矩 形波fvlk之二信號的電路。作為此VCC：22的三角波fVC0 及矩形波fclk係被輸入至第一驅動電路7。第一驅動電 路7係以第一分頻電路16將自頻率拂掠振盪器6之 VCC22所輸出的矩开多波fclk予以分頻，而產生作用比成 為50%之二相位的信號。將此二相位的信號輸入至第一 電晶體Q1、Q2，而交相地開關Q1、Q2，藉以於q 1、 本紙張尺度適用中國國家標準（CNS ) A4规格（210X297公釐） (請先閲讀背面之注^^項再填寫本頁)427101 Consumer Cooperatives of the Central Standards Bureau, Ministry of Economic Affairs, Yin Fan Λ7 B7 V. Description of Invention (11) The rectifier circuit 18 is converted into a DC voltage. The first comparator 19 compares the predetermined value of the tube current Io with the reference voltage Vref. When the output signal of the first comparator 19 is greater than the reference voltage Vref when the DC voltage obtained from the tube current 10 is greater, a signal for increasing the driving frequency of the first piezoelectric transformer 2 is output to the frequency sweep oscillator 6. On the other hand, when the DC voltage is smaller than the reference voltage Vref, a signal is output to decrease the driving frequency fk of the first piezoelectric transformer 2. The frequency sweeping oscillator 6 to which this signal is input is converted by the integrating circuit 21 to the output signal of the binary of the first comparator 19 into an analog signal, and is output to the VC022 and the comparator 20. VC022, which generates a frequency corresponding to the output signal of this ratio, is a vibrating circuit with a frequency that is twice the output drive frequency fk. Although this oscillation frequency is higher as the integrating circuit 21 is lower, the integral is compared in a comparator 20. The output voltage of the circuit 21 and the reference voltage Vmax, and when the output voltage exceeds the reference voltage Vmax, that is, when the oscillation frequency drops to the lowest frequency determined by the reference voltage Vmax, a reset signal is output to the integrating circuit 21 'and sweep the oscillation frequency of VCC22 from the lowest frequency to the highest frequency at high speed ^ VCC22 is a circuit that outputs two signals of triangle wave fvc0 and rectangular wave fvlk in the frequency range from this lowest frequency to the highest frequency. The triangular wave fVC0 and the rectangular wave fclk of VCC: 22 are input to the first driving circuit 7. The first driving circuit 7 divides the moment-open multi-wave fclk output from the VCC 22 of the frequency sweeping oscillator 6 by the first frequency dividing circuit 16 to generate a signal with an effect ratio of two phases of 50%. This two-phase signal is input to the first transistors Q1 and Q2, and the phase-to-phase switches Q1 and Q2 are used to make q 1. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) (please first (Read the note ^^ on the back and fill out this page)
427101 經濟部中央標準局員工消費合作社印裝 Λ7 B7 五、發明説明（12 ) ~ Q2中之*纟成為導通（ΟΝ)時，將電流能源儲存於連接 至此電日曰體的第一線圈L1、L2,成為不導通（〇ff)時， 被儲存的電流能源藉由第一線圈及第一壓電變壓器2之 輸入電容的_聯共振，而當作電壓源能放出，進而產生 第一之二相位的半波正弦波電壓Vdl、Vd2。此半波正 弦波電壓係被交互地輸入至第—壓電變壓器2之一次侧 電極2a的兩電極，等效地當作正弦波電壓。因此，第一 壓電變壓器2係藉由驅動頻率汉及對應於第一冷陰極管 3的阻抗，而將輸出電壓v〇輸出至二次側電極2b，進而 將第一冷陰極管3點燈。 其次，將副方塊25顯示於第4圖而加以說明。其包 括第二壓電變壓器2、第二冷陰極管3、第二驅動電路7、 第二負載電流比較電路8及輸出控制作為第二驅動電路 7之輸出之二相位之半波正弦波電壓之電壓峰值之信號 的驅動電壓控制電路11。由於第二負載電流比較電路8 係與第一負載電流比較電路8相同的構造，故藉由流至 第二冷陰極管3之管電流ίο受第二基基準電壓Vref所決 定的既定值，而輸出顯示大或小之二進位的信號。此二 進位的信號係被輸入至驅動電壓控制電路11，而被變換 成類比量的信號Vc β且此信號被輪入至第二驅動電路 7。此第二驅動電路7係與第一驅動電路7相同的構造， 故產生驅動第二壓電變壓器2之第二之二位相的半波正 弦波電壓Vdl、Vd2。被輸入第二驅動電路7之驅動電 壓控制電路11的輸出信號Vc係被輸入至第二比較器 本紙張尺度適用中國國家標準（cns)A4規格（210X297公釐） ίχ------、玎------0;— t r . (請先閲讀背面之注意事項再填寫本頁) 42710 Λ7 B7 經濟部中央標隼局貝工消費合作社印衆 五、發明説明（13 ) I5 ’而與自第一頻率拂掠振盪器石之 角波fVC〇比較。且第二比較器15係輪出控輪^的三 Q;的信號。藉由此信號來變化第二電晶體 不導通的比率，而控制輸入至第二線圈u、^ p427101 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs Λ7 B7 5. When * 纟 in the description of the invention (12) ~ Q2 becomes conductive (ON), the current energy is stored in the first coil L1 connected to this electric body. When L2 becomes non-conducting (0ff), the stored current energy is discharged as a voltage source through the _-link resonance of the first coil and the input capacitance of the first piezoelectric transformer 2 to generate the first two Phase half-wave sine wave voltages Vdl, Vd2. This half-wave sine-wave voltage is alternately input to both electrodes of the primary-side electrode 2a of the first piezoelectric transformer 2 and is equivalently regarded as a sine-wave voltage. Therefore, the first piezoelectric transformer 2 outputs the output voltage v0 to the secondary-side electrode 2b by driving the frequency and the impedance corresponding to the first cold cathode tube 3, and then the first cold cathode tube 3 is turned on. . Next, the sub-block 25 is shown in FIG. 4 and described. It includes a second piezoelectric transformer 2, a second cold cathode tube 3, a second drive circuit 7, a second load current comparison circuit 8, and an output control circuit which is a two-phase half-wave sine-wave voltage of the output of the second drive circuit 7. The voltage peak signal drives the voltage control circuit 11. Since the second load current comparison circuit 8 has the same structure as the first load current comparison circuit 8, the tube current flowing to the second cold cathode tube 3 is determined by a predetermined value determined by the second base reference voltage Vref, and The output signals a large or small binary. The binary signal is input to the driving voltage control circuit 11 and is converted into an analog signal Vc β and the signal is rounded to the second driving circuit 7. This second driving circuit 7 has the same structure as the first driving circuit 7, so that the half-wave sine wave voltages Vd1, Vd2 of the second two-phase of the second piezoelectric transformer 2 are generated. The output signal Vc input to the driving voltage control circuit 11 of the second driving circuit 7 is input to the second comparator. The paper size applies the Chinese National Standard (cns) A4 specification (210X297 mm).玎 ------ 0; — tr. (Please read the precautions on the back before filling this page) 42710 Λ7 B7 The Central Bureau of Standards, Ministry of Economic Affairs, Shellfish Consumer Cooperatives, India 5. V. Invention Description (13) I5 'And Compared with the angular wave fVC0 that swept the oscillator stone from the first frequency. And the second comparator 15 is a signal of three Q; By this signal, the ratio of non-conduction of the second transistor is changed, and the control input to the second coil u, ^ p
值，藉以控制驅動第二壓電變壓器2之第— 、°'L 半波正弦波電壓Vdl、Vd2的峰值：：：相位之 動電壓控制電路11的内部電路例。例如，若流二冷 陰極管3的管電流IgA於既定值，則自第負載電流:較 電路8的二比較器19輸出高位準的信號。依據此高位準 的信號而使SW1成為0N ’且SW2成為〇FF，經由定電 流源而被充電至電容Ci ’故電容Ci的電壓Vi增加。此 電壓Vi係被輸入至積分電路23的反相端子，且作為波 封產生電路12之輸出的Venv被輸入至非反相端子。此 Verw係於冷陰極管3點燈時成為高位準的信號，而若電 容Ci的電壓Vi高於yenv，則積分電路23的輸出Vc降 低。此Vc係被輸入至第二驅動電路7之第二比較器15 的反相端子，而與被輸入至非反相端子之作為頻率拂掠 振廬Is 6之VC022之輸出的三角波fvco比較，故若積分 電路23的輸出VC降低，則自第二比較器15輸出於使第 一電晶體Q3不導通期間之作用比變大的信號Q反之，若 管電流1〇較既定值小，則自第二比較器i 9輸出低位準的 信號。依據此低位準的信號而使SW1成為OFF，且SW2 成為ON ’經由定電流源而電容Ci被放電，故電容Ci的 電壓Vi減少。若電壓Vi低於Venv，則積分電路23的輸 16 本紙張尺度適用中國國家標準（CNS ) A4规格C 21〇Χ297公釐） (請先閱玫背面之ii.-意事項再填寫本頁〕 訂 經濟部t央標準局員工消費合作社印製 42710 1 Λ7 B7 -----' ----- _____ _ 五、發明説明（14) 出Vc增加。若積分電路23的輸出Vc增加。則自第二比 較器15輸出於使第二電晶體q3導通期間之作用比變大 的信號。 此動作波形圖係顯示於第7圖。藉由控制第二之二 相位之半波正弦波電壓Vdl、Vd2的峰值，而將流至第 二冷陰極管3的管電流1〇控制成既定的電流值。由於作 為頻率拂掠振盪器6之VC022之輸出的矩形波fclk被輸 入至第二驅動電路7的分頻電路16，故此第二之二相位 之半波正弦波電壓Vdl、Vd2的頻率成為與第_之二相 位之半波正弦波電壓Vdl、Vd2的頻率同步的頻率作。 又如第1圖所示’可並聯副方塊25，而可作η根冷陰極 管3的點燈》 其次’說明調光方塊26 ^於第1圖中，調光方塊包 括：調光電路9，將用以調光頻率fc來間歇控制第一及 第二壓電變壓器2的調光信號輸出至頻率拂掠振盪器6 及波封產生電路12 ;以及波封產生電路12，將抑制包 含於壓電變壓器2之驅動電壓Vdl、Vd2的頻率成分之 間歇地控制所產生之局错波的信號輸出至第一驅動電路 7及驅動電壓控制電路11。調光電路9包括三角波振盈 器13，產生較驅動頻率fk充分低且不閃爍的頻率；以及 比較器14，比較作為此三角波振盪器13之輪出的三角 波與調光電壓，而決定調光信號的作用比。自調光電路9 所輸出的調光信號係於調光電壓較三角波高的場合經常 成為低位準，而隨著調光電壓的降低，進而高位準的作 17 本紙张尺度適用中國國家標準（cns ) A4規格（210X297公釐1 ~" 〜 ---- (讀先閱讀背面之注意事碩再填寫本頁) -訂 427101 Λ7 B7 經濟部中央標隼局員工消費合作社印製 五、發明説明（15 ) 用比漸漸地變長。此調光信號係被輸入至頻率拂掠振I 器6的積分電路21(參照第3圖），而於調光信號為高位準 的期間，亦即停止壓電變壓器2之驅動的期間，即使第 一冷陰極管1〇降低，亦可保持作為積分電路21之輸出之 類比量的信號不變化。因此，VC022所產生的頻率不變 化，而再驅動第一壓電變壓器2時，可以與停止前之頻 率相同的頻率來驅動。 又此調光信號係被輸入至波封產生電路12。第6圖 係顯示此波封產生電路12的内部電路例。此電路包括開 關、定電流源及電容，而若調光信號成為低位準，則SW3 成為導通，而SW4成為不道通，故自定電流源充電至電 容Cenv ;且若調光信號成為高位準，則SW3成為不導 通，而S W4成為導通，故自定電流源使電容Cenv放電》 因此，波封產生電路12的輸出係成為調光信號的反相波 形於上昇及下降時具有傾斜的梯形波Venv。自此波封產 生電路12所輸出的梯形波Venv係被輸入至第一驅動電 路7的第一比較器15(參照第3圖）及驅動電壓控制電路 11(參照第4圖）的積分電路23(參照第5圖），故於第一及 第二電晶體Q3自不導通狀態成為導通狀態時及自導通 狀態成為不導通狀態時的作用比漸漸增減，因而第一及 第二壓電變壓器2之二相位的半波正弦波電壓Vdl 、 Vd2係被調變成梯形波的波封。此動作波形圖係顯示於 第8圖《如此，將半波正弦波電壓vdi、Vd2調變成梯 形波的波封的結果，而限制施加於壓電變壓器2之驅動 18 本紙張尺度適用中國國家標隼（CNS) A4規格（2丨0X29*7公釐） (請先閲讀背面之注意事項再填寫本頁) i 衣. 訂Value to control the driving of the second-,-'' half-wave sine wave voltages Vdl, Vd2 of the second piezoelectric transformer 2: The internal circuit example of the phase dynamic voltage control circuit 11. For example, if the tube current IgA of the second cold cathode tube 3 flows at a predetermined value, a higher-level signal is output from the second load current: the second comparator 19 of the circuit 8. Based on this high-level signal, SW1 becomes 0N 'and SW2 becomes 0FF, and is charged to the capacitor Ci' via the constant current source, so the voltage Vi of the capacitor Ci increases. This voltage Vi is input to the inverting terminal of the integrating circuit 23, and Venv, which is an output of the envelope generating circuit 12, is input to the non-inverting terminal. This Verw is a high-level signal when the cold-cathode tube 3 is turned on, and if the voltage Vi of the capacitor Ci is higher than yenv, the output Vc of the integrating circuit 23 decreases. This Vc is input to the inverting terminal of the second comparator 15 of the second driving circuit 7, and is compared with the triangular wave fvco that is input to the non-inverting terminal as the output of VC022, which is a frequency sweeping oscillator 6. If the output VC of the integrating circuit 23 decreases, the signal Q output from the second comparator 15 during the period when the first transistor Q3 is not conducting becomes larger, and vice versa. If the tube current 10 is smaller than a predetermined value, The two comparators i 9 output a low-level signal. SW1 is turned off and SW2 is turned on according to this low-level signal, and the capacitor Ci is discharged through the constant current source, so the voltage Vi of the capacitor Ci decreases. If the voltage Vi is lower than Venv, then the output of the integrating circuit 23 is 16 The paper size is applicable to the Chinese National Standard (CNS) A4 specification C 21〇 × 297 mm) (please read the ii. On the back of the rose first, and then fill in this page) Printed by the Consumers 'Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 42710 1 Λ7 B7 -----' ----- _____ _ V. Description of the invention (14) The output Vc is increased. If the output Vc of the integration circuit 23 is increased, then A signal outputted from the second comparator 15 during the conduction period of the second transistor q3 becomes larger. This operation waveform diagram is shown in Fig. 7. By controlling the half-wave sine wave voltage Vdl of the second phase And the peak value of Vd2, and the tube current 10 flowing to the second cold cathode tube 3 is controlled to a predetermined current value. The rectangular wave fclk which is the output of VC022 of the frequency sweep oscillator 6 is input to the second driving circuit. The frequency division circuit 16 of 7, therefore, the frequencies of the second half-phase sine wave voltages Vdl, Vd2 of the second phase become a frequency synchronized with the frequency of the second half-phase sine wave voltages Vdl, Vd2. As shown in Fig. 1 ', the secondary block 25 can be connected in parallel, and it can be used as the point of η cold cathode tubes 3 》 Next, the description of the dimming block 26 ^ In the first figure, the dimming block includes: a dimming circuit 9 that outputs a dimming signal for dimming the frequency fc to intermittently control the first and second piezoelectric transformers 2 to The frequency swept oscillator 6 and the wave envelope generating circuit 12; and the wave envelope generating circuit 12 suppress the signal output of the local error wave generated intermittently by suppressing the frequency components of the driving voltages Vdl, Vd2 included in the piezoelectric transformer 2 To the first driving circuit 7 and the driving voltage control circuit 11. The dimming circuit 9 includes a triangular wave vibrator 13 that generates a frequency sufficiently lower than the driving frequency fk and does not flicker; and a comparator 14 that compares the triangular wave oscillator 13 The triangle wave and the dimming voltage that come out of the wheel determine the ratio of the dimming signal. The dimming signal output by the self-dimming circuit 9 is often a low level when the dimming voltage is higher than the triangular wave. The paper size is reduced to a high level. 17 This paper size is applicable to the Chinese National Standard (cns) A4 specification (210X297 mm 1 ~ " ~ ---- (Read the precautions on the back before filling in this page)-Order 427101 Λ7 B7 Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 5. Description of the invention (15) The ratio gradually becomes longer. This dimming signal is input to the integrating circuit 21 of the frequency sweeping vibrator 6 (refer to Figure 3). ), And during the period when the dimming signal is at a high level, that is, when the driving of the piezoelectric transformer 2 is stopped, even if the first cold-cathode tube 10 is lowered, the analog signal of the output of the integrating circuit 21 can be maintained. Therefore, the frequency generated by VC022 does not change, and when the first piezoelectric transformer 2 is driven again, it can be driven at the same frequency as the frequency before stopping. The dimming signal is input to the wave seal generating circuit 12. Fig. 6 shows an example of the internal circuit of this wave envelope generating circuit 12. This circuit includes a switch, a constant current source, and a capacitor. If the dimming signal becomes low, SW3 becomes conductive and SW4 becomes non-conductive, so the self-defined current source is charged to the capacitor Cenv; and if the dimming signal becomes high Then, SW3 becomes non-conducting, and SW4 becomes conductive, so the self-defined current source discharges the capacitor Cenv. Therefore, the output of the wave seal generating circuit 12 becomes the inverted waveform of the dimming signal, which has an inclined trapezoidal shape when it rises and falls. Wave Venv. The trapezoidal wave Venv output from the wave seal generating circuit 12 is input to the first comparator 15 (see FIG. 3) of the first drive circuit 7 and the integrating circuit 23 of the drive voltage control circuit 11 (see FIG. 4). (Refer to FIG. 5). Therefore, the first and second piezoelectric transformers gradually increase and decrease in the ratios when the first and second transistors Q3 change from the non-conductive state to the conductive state and when the self-conductive state becomes the non-conductive state. The two-phase two-phase half-wave sine wave voltages Vdl and Vd2 are adjusted into trapezoidal wave envelopes. This action waveform diagram is shown in Figure 8 "So, the half wave sine wave voltages vdi, Vd2 are turned into trapezoidal wave envelopes, and the drive applied to the piezoelectric transformer 2 is restricted.隼 (CNS) A4 size (2 丨 0X29 * 7mm) (Please read the precautions on the back before filling this page) i Clothing. Order
A 經濟部中央標準局員工消費合作杜印製 427101 Λ7 B7 五、發明説明（16 ) 頻率的高頻成分，故抑制壓電變壓器2的寄生振動，而 可減低壓電變壓器2及支持機構10之可聽音的產生。又 由於波封產生電路12的輸出Venv係分別被輸入至主方 塊24及副方塊25，故調光周期均同步。 ' 由以上的說明可知，有效率地將複數根冷陰極管3 穩定地並聯點燈之壓電變壓器的驅動電路係藉由一個主 方塊、一個以上副方塊24及一個調光方塊的組合，而可 同步地驅動此驅動頻率及調光頻率，進而亦可減低可聽 音的產生。 其次，說明本發明的其他實施例。第2圖所示的實 施例與第1圖所示者不同之處在於：去除第1圖的波封 產生電路12，且自調光電路所輸出的調光信號被輸入至 驅動電壓控制電路11。此乃於驅動負載時所產生的可聽 音成為問題的場合’可提供有效率且穩定地將複數冷陰 極管3點燈之壓電變壓器2的驅動電路。 【發明效果】 第一效果係於複數根冷陰極管3並聯點燈的場合， 不產生偏差。由於同步驅動驅動頻率及/或調光頻率之 故。藉由均使驅動頻率同步而無冷陰極管3相互間之浮 動電容之耦合所造成之管電流的調幅β且藉由均使調光 頻率同步，而於壓電變壓器2之驅動開始及停止時的高 壓經由冷陰極管3相互間之浮動電容所造成的耦合而不 變化流過其他冷陰極管的管電流值，故可防止電路動作 成為不穩定。 19 本紙張尺度適财關家標準（CNS ) A4規格（21GX297公楚） ---------------IT------ (請先閲讀會面之注t*事項再填寫本頁) - 427101 Λ7 B7 五、發明説明（17 ) 第一效果係由於均同步驅動驅動頻率而將全部管電 流控制成一定’故亮度成為一定。由於壓電變壓器2之 共振頻率和昇壓特性以及冷陰極管3的電壓-電流特性具 有偏差’故僅使驅動頻率同步’而各各管電流值成分散， 進而產生亮度差。為了吸收此等偏差，控制壓電變壓器2 之驅動電壓的峰值，而藉由使管電流成為一定，進而使 亮度成為一定。 第三效果係於管長度長之冷陰極管3複數根並聯點 燈的場合’可減低於PWM調光方式之可聽音之產生的增 大。由於壓電變壓器2的驅動電壓低，故藉由降低機械 的振動速度，而可減低可聽音’且藉由波封產生電路12 來減低包含於壓電變壓器2之驅動頻率之時間分割驅動 所造成高頻成分，而亦可減低壓電變壓器2之寄生振動 的產生》其結果’可抑制壓電變壓器2及其支持機構1〇 所產生的可聽音。 【圖式簡單說明】 第1圖係依據本發明之一實施例的方塊圖。 第2圖係依據本發明之另一實施例的方塊圖。 經濟部中央標準局員工消費合作社印製 (請先閲讀背面之注意事項再填寫本頁) 第3圖係依據本發明之一實施例的主方塊圖。 第4圖係依據本發明之一實施例的副方塊圖。 第5圖係依據本發明之一實施例之驅動電壓控制電 路的方塊圖。 第6圖係依據本發明之一實施例之波封產生電路的 方塊圖。 20 尽紙張尺度適用中國國家標準（CNS ) M規格⑺〇><297公釐） Λ7 4271 Ο 1 Β7 1 -.- 五、發明説明（18 ) 第7圖係驅動電壓動作的波形圖。 第8圖係調光動作的波形圖。 第9圖係壓電變壓器的昇壓特性圖。 第10圖係顯示冷陰極管之電壓與電流的特性圖。 第11圖係依據複數串聯點燈之習知技術的方塊圖。 第12圖係依據複數串聯點燈之習知技術的方塊圖。 第13圖係依據第12圖之電路之動作的波形圖。 第14圖（a)係顯示壓電變壓器之輸出電力與機械的 振動速度之關係的特性圖；第14圖（b)係顯示壓電變壓器 之輸出電力與機械的溫度上昇之關係的特性圖；第14圖 (c)係係顯示壓電變壓器之輸出電力與效率之關係的特性 圖。 第15圖係依據第12圖之電路之冷陰極管相互間的 浮動電容干涉圖。 【符號說明】 1〜換流器；2〜壓電變壓器；2a〜一次側電極；2b〜 二次側電極；3〜冷陰極管；4〜積分器；5〜V-F變頻器； 6〜頻率拂掠振鹽器；7!驅動電路；8〜負載電流比較電 路；9〜調光電路；10〜支持機構；11〜驅動電壓控制電 路；12〜波封產生電路；13〜三角波振盪器；14〜比較 器；15〜比較器；16分頻電路；17〜電流-電壓變換電 路；18〜整流電路；19〜比較器；20〜比較器；21〜積分 電路；22〜VCO ; 23〜積分電路；24〜主方塊；25〜副方 塊；26〜調光方塊。 21 本紙張尺度適用中^國國家標準（CNS ) A4規格（210X297公釐) ' (請先閱讀背面之注意事項再填寫本頁) ,-11 經濟部中央標準局員工消费合作社印製A Consumption cooperation between employees of the Central Bureau of Standards of the Ministry of Economic Affairs Du printed 427101 Λ7 B7 V. Description of the invention (16) The high-frequency component of the frequency suppresses the parasitic vibration of the piezoelectric transformer 2 and can reduce the low-voltage electric transformer 2 and the supporting mechanism 10 Audible sound generation. Since the output Venv of the wave seal generating circuit 12 is input to the main block 24 and the sub block 25, respectively, the dimming periods are synchronized. '' From the above description, it can be seen that the driving circuit of a piezoelectric transformer that stably lights a plurality of cold cathode tubes 3 in parallel in a stable manner is a combination of one main block, one or more sub blocks 24, and one dimming block. This driving frequency and dimming frequency can be driven synchronously, thereby reducing the generation of audible sound. Next, other embodiments of the present invention will be described. The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. 1 in that the wave seal generating circuit 12 in FIG. 1 is removed, and the dimming signal output from the self-dimming circuit is input to the driving voltage control circuit 11 . This is a case where audible sound generated when driving a load becomes a problem 'can provide a driving circuit for the piezoelectric transformer 2 which can efficiently and stably illuminate a plurality of cold cathodes 3. [Effect of the Invention] The first effect is that when a plurality of cold cathode tubes 3 are lit in parallel, no deviation occurs. Due to synchronous drive driving frequency and / or dimming frequency. By synchronizing the driving frequencies without the coupling of the floating capacitors of the cold cathode tubes 3 with each other, the tube current amplitude β is caused by the synchronization of the dimming frequencies, and when the driving of the piezoelectric transformer 2 is started and stopped The coupling of the high voltage through the floating capacitors of the cold-cathode tubes 3 does not change the value of the tube current flowing through the other cold-cathode tubes, so that the circuit operation can be prevented from becoming unstable. 19 This paper is suitable for financial standards (CNS) A4 specification (21GX297). --------------- IT ------ (Please read the note t * Please fill in this page again)-427101 Λ7 B7 V. Description of the invention (17) The first effect is that all the tube currents are controlled to be constant because the driving frequency is synchronously driven, so the brightness becomes constant. Since the resonance frequency and step-up characteristics of the piezoelectric transformer 2 and the voltage-current characteristics of the cold-cathode tube 3 have deviations ', only the driving frequency is synchronized' and the current values of the respective tubes are dispersed, thereby generating a brightness difference. In order to absorb these deviations, the peak value of the driving voltage of the piezoelectric transformer 2 is controlled, and the tube current is made constant, and the brightness is made constant. The third effect is that when a plurality of cold-cathode tubes with a long tube length are lit in parallel, it can reduce the increase of the audible sound generated by the PWM dimming method. Since the driving voltage of the piezoelectric transformer 2 is low, the audible sound can be reduced by reducing the vibration speed of the machine, and the time-segment driving mechanism of the driving frequency included in the piezoelectric transformer 2 can be reduced by the envelope generating circuit 12. Resulting in high-frequency components, but also can reduce the generation of parasitic vibration of the low-voltage electric transformer 2 "Results" can suppress the audible sound generated by the piezoelectric transformer 2 and its support mechanism 10. [Brief description of the drawings] FIG. 1 is a block diagram according to an embodiment of the present invention. FIG. 2 is a block diagram according to another embodiment of the present invention. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the notes on the back before filling this page). Figure 3 is a main block diagram according to an embodiment of the present invention. FIG. 4 is a sub-block diagram according to an embodiment of the present invention. Fig. 5 is a block diagram of a driving voltage control circuit according to an embodiment of the present invention. Fig. 6 is a block diagram of a wave envelope generating circuit according to an embodiment of the present invention. 20 Chinese paper standard (CNS) M specification ⑺〇 > < 297 mm) Λ7 4271 〇 1 Β7 1 -.- 5. Description of the invention (18) Figure 7 is a waveform diagram of driving voltage operation. Fig. 8 is a waveform diagram of a dimming operation. Fig. 9 is a step-up characteristic diagram of a piezoelectric transformer. Figure 10 is a graph showing the voltage and current characteristics of a cold cathode tube. FIG. 11 is a block diagram based on the conventional technique of plural series lighting. FIG. 12 is a block diagram based on the conventional technique of plural series lighting. FIG. 13 is a waveform diagram of the operation of the circuit according to FIG. 12. Figure 14 (a) is a characteristic diagram showing the relationship between the output power of the piezoelectric transformer and the vibration speed of the machine; Figure 14 (b) is a characteristic diagram showing the relationship between the output power of the piezoelectric transformer and the temperature rise of the machine; FIG. 14 (c) is a characteristic diagram showing the relationship between the output power and efficiency of the piezoelectric transformer. Fig. 15 is a floating capacitance interference diagram between cold cathode tubes according to the circuit of Fig. 12. [Symbol description] 1 ~ converter; 2 ~ piezo transformer; 2a ~ primary side electrode; 2b ~ secondary side electrode; 3 ~ cold cathode tube; 4 ~ integrator; 5 ~ VF inverter; 6 ~ frequency Salt-sweeping device; 7! Drive circuit; 8 ~ load current comparison circuit; 9 ~ dimming circuit; 10 ~ support mechanism; 11 ~ drive voltage control circuit; 12 ~ wave seal generation circuit; 13 ~ triangle wave oscillator; 14 ~ Comparator; 15 to comparator; 16 frequency division circuit; 17 to current-voltage conversion circuit; 18 to rectifier circuit; 19 to comparator; 20 to comparator; 21 to integrating circuit; 22 to VCO; 23 to integrating circuit; 24 to main block; 25 to sub block; 26 to dimming block. 21 This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) '(Please read the precautions on the back before filling out this page),-11 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs